20 Degrees Retarded..........

[Ttoyota]

Did you ever figure out your issue?

 

[redfishsc]

Disconnect the cam retard sensor from behind the dist and clean it with some CRC elec contact cleaner.

If its not changing cam retard angle when you twist the dist, then it seems like the sensor is hoopajooped or the connector is not making contact

 

[big_mike]

I was having a hard start issue with popping in the exhaust, I knew the timing was off somehow but not why. It had a cam sensor code so I replaced it in the distributor. Still wouldn't start though until I had it reset with a scanner. Hasn't done it again since. Mechanic told me it was about 20* out when he checked it.

 

[Bodageta1995]

This is probably unrelated but sometimes the ring with the timing mark on the harmonic balancer slips and changes the clocking of the mark or atleast it does on other GM products (Late 80's Corvette for example). Again, probably totally not the issue based on symptoms but wanted to mention it as sometimes that takes a long time to figure out.